Functional Characterization of Phospholipid N-Methyltransferases from Arabidopsis and Soybean

Keogh, Matthew R.; Courtney, Polly D.; Kinney, Anthony J.; Dewey, Ralph E.

doi:10.1074/jbc.m109.005991

Cited by 41 publications

(61 citation statements)

References 41 publications

(51 reference statements)

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“…Furthermore, the expression of the PEAMT genes encoding a key enzyme of choline synthesis was induced in lpcat1 lpcat2-2 (Figure 9; see Supplemental Data Set 2 online). These results indicated that the metabolic response of increased de novo PC synthesis involves a series of highly orchestrated molecular steps (Tasseva et al, 2004;Keogh et al, 2009). The weak phenotype of reductions of 18:2 and 18:3 in the TAG of lpcat1 lpcat2-2 also supports the notion that Arabidopsis developing seeds have the capacity to channel 18:1 into PC for desaturation to 18:2 and 18:3 beyond the Lands cycle as well as metabolic plasticity for mobilizing PUFAs into TAG.…”

Section: Discussionmentioning

confidence: 91%

Metabolic Interactions between the Lands Cycle and the Kennedy Pathway of Glycerolipid Synthesis in Arabidopsis Developing Seeds

et al. 2012

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It has been widely accepted that the primary function of the Lands cycle is to provide a route for acyl remodeling to modify fatty acid (FA) composition of phospholipids derived from the Kennedy pathway. Lysophosphatidylcholine acyltransferase (LPCAT) is an evolutionarily conserved key enzyme in the Lands cycle. In this study, we provide direct evidence that the Arabidopsis thaliana LPCATs, LPCAT1 and LPCAT2, participate in the Lands cycle in developing seeds. In spite of a substantially reduced initial rate of nascent FA incorporation into phosphatidylcholine (PC), the PC level in the double mutant lpcat1 lpcat2-2 remained unchanged. LPCAT deficiency triggered a compensatory response of de novo PC synthesis and a concomitant acceleration of PC turnover that were attributable at least in part to PC deacylation. Acyl-CoA profile analysis revealed complicated metabolic alterations rather than merely reduced acyl group shuffling from PC in the mutant. Shifts in FA stereospecific distribution in triacylglycerol of the mutant seed suggested a preferential retention of saturated acyl chains at the stereospecific numbering (sn)-1 position from PC and likely a channeling of lysophosphatidic acid, derived from PC, into the Kennedy pathway. Our study thus illustrates an intricate relationship between the Lands cycle and the Kennedy pathway.

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Section: Discussionmentioning

confidence: 91%

Metabolic Interactions between the Lands Cycle and the Kennedy Pathway of Glycerolipid Synthesis in Arabidopsis Developing Seeds

et al. 2012

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“…6 and 7). PtdMEA is normally a quantitatively minor and transitory intermediate in PtdCho synthesis (34,35,37). Under the growth conditions used, the elevated 34:3-PtdMEA species in lipid fractions of atpmeamt was not associated with a deleterious phenotype.…”

Section: Discussionmentioning

confidence: 99%

“…Again, the failure to recover this plant cDNA probably reflects its low abundance or absence in the library. Because there were no differences in growth or lipid profiles between wild-type and PLMT-deficient Arabidopsis plants (37), this enzyme may play a more important role in other plant species, such as soybean, where the Ptd-base route for PtdCho synthesis predominates (9, 10, 37). Bolognese and McGraw (18) also noted the lack of complementation by plant PLMT when they used the same strategy to clone AtPEAMT.…”

Section: Discussionmentioning

confidence: 99%

“…Few reports document the contribution of PtdMEA or PtdDEA to the lipid composition of plants (34,35,37), but the capacity to produce phospholipid membranes containing PtdMEA may be a more general feature of plants. The comparison reported by Keogh et al (37) with respect to the lipid composition between atplmt mutant and wild-type Arabidopsis shows PtdMEA to be present among the phospholipids found in both lines.…”

Section: Discussionmentioning

confidence: 99%

“…An enzyme using only PDEA as substrate, for example, would not have functionally complemented the yeast phospholipid mutant following our selection strategy. We also did not clone the recently identified Arabidopsis phospholipid N-methyltransferase (AtPLMT) that is able to methylate PtdMEA and PtdDEA (37). Again, the failure to recover this plant cDNA probably reflects its low abundance or absence in the library.…”

Section: Discussionmentioning

confidence: 99%

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Identification of Phosphomethylethanolamine N-Methyltransferase from Arabidopsis and Its Role in Choline and Phospholipid Metabolism

BeGora¹,

MacLeod²,

McCarry

et al. 2010

Journal of Biological Chemistry

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Three sequential methylations of phosphoethanolamine (PEA) are required for the synthesis of phosphocholine (PCho) in plants. A cDNA encoding an N-methyltransferase that catalyzes the last two methylation steps was cloned from Arabidopsis by heterologous complementation of a Saccharomyces cerevisiae cho2, opi3 mutant. The cDNA encodes phosphomethylethanolamine N-methyltransferase (PMEAMT), a polypeptide of 475 amino acids that is organized as two tandem methyltransferase domains. PMEAMT shows 87% amino acid identity to a related enzyme, phosphoethanolamine N-methyltransferase, an enzyme in plants that catalyzes all three methylations of PEA to PCho. PMEAMT cannot use PEA as a substrate, but assays using phosphomethylethanolamine as a substrate result in both phosphodimethylethanolamine and PCho as products. PMEAMT is inhibited by the reaction products PCho and S-adenosyl-L-homocysteine, a property reported for phosphoethanolamine N-methyltransferase from various plants. An Arabidopsis mutant with a T-DNA insertion associated with locus At1g48600 showed no transcripts encoding PMEAMT. Shotgun lipidomic analyses of leaves of atpmeamt and wild-type plants generated phospholipid profiles showing the content of phosphatidylmethylethanolamine to be altered relative to wild type with the content of a 34:3 lipid molecular species 2-fold higher in mutant plants. In S. cerevisiae, an increase in PtdMEA in membranes is associated with reduced viability. This raises a question regarding the role of PMEAMT in plants and whether it serves to prevent the accumulation of PtdMEA to potentially deleterious levels.Choline occurs in plants as free choline, phosphocholine (PCho) 2

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Targeting the lipid metabolic pathways for the treatment of malaria

Mamoun

Prigge

Vial

2009

Drug Development Research

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The control and eventual eradication of human malaria is considered one of the most important global public health goals of the 21st Century. Malaria, caused by intraerythrocytic protozoan parasites of the genus Plasmodium, is by far the most lethal and among the most prevalent of the infectious diseases. Four species of Plasmodium (P. falciparum, P. malariae, P. ovale, and P. vivax) are known to be infectious to humans, and more recent cases of infection due to P. knowlesi also have been reported. These species cause approximately 300 million annual cases of clinical malaria resulting in around one million deaths mostly caused by P. falciparum. The rapid emergence of drug-resistant Plasmodium strains has severely reduced the potency of medicines commonly used to treat and block the transmission of malaria and threatens the effectiveness of combination therapy in the field. New drugs that target important parasite functions, which are not the target of current antimalarial drugs, and have the potential to act against multi-drug-resistant Plasmodium strains are urgently needed. Recent studies in P. falciparum have unraveled new metabolic pathways for the synthesis of the parasite phospholipids and fatty acids. The present review summarizes our current understanding of these pathways in Plasmodium development and pathogenesis, and provides an update on the efforts underway to characterize their importance using genetic means and to develop antimalarial therapies targeting lipid metabolic pathways.

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Functional Characterization of Phospholipid N-Methyltransferases from Arabidopsis and Soybean

Cited by 41 publications

References 41 publications

Metabolic Interactions between the Lands Cycle and the Kennedy Pathway of Glycerolipid Synthesis in Arabidopsis Developing Seeds

Metabolic Interactions between the Lands Cycle and the Kennedy Pathway of Glycerolipid Synthesis in Arabidopsis Developing Seeds

Identification of Phosphomethylethanolamine N-Methyltransferase from Arabidopsis and Its Role in Choline and Phospholipid Metabolism

Targeting the lipid metabolic pathways for the treatment of malaria

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